reactos/win32ss/drivers/videoprt/ddc.c

   1 /*
   2  * VideoPort driver
   3  *
   4  * Copyright (C) 2002, 2003, 2004 ReactOS Team
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #include "videoprt.h"
  23
  24 #define NDEBUG
  25 #include <debug.h>
  26
  27 #define DDC_EEPROM_ADDRESS  0xA0
  28
  29 /* PRIVATE FUNCTIONS **********************************************************/
  30
  31 #define LOW               0
  32 #define HIGH              1
  33 #define WRITE             0
  34 #define READ              1
  35 #define READ_SDA()        (i2c->ReadDataLine(HwDeviceExtension))
  36 #define READ_SCL()        (i2c->ReadClockLine(HwDeviceExtension))
  37 #define WRITE_SDA(state)  (i2c->WriteDataLine(HwDeviceExtension, state))
  38 #define WRITE_SCL(state)  (i2c->WriteClockLine(HwDeviceExtension, state))
  39
  40 static LARGE_INTEGER HalfPeriodDelay = {{0, 70}};
  41 #define DELAY_HALF()      KeDelayExecutionThread(KernelMode, FALSE, &HalfPeriodDelay)
  42
  43
  44 static BOOL
  45 I2CWrite(PVOID HwDeviceExtension, PI2C_CALLBACKS i2c, UCHAR Data)
  46 {
  47    UCHAR Bit;
  48    BOOL Ack;
  49
  50    /* transmit data */
  51    for (Bit = (1 << 7); Bit != 0; Bit >>= 1)
  52      {
  53         WRITE_SCL(LOW);
  54         WRITE_SDA((Data & Bit) ? HIGH : LOW);
  55         DELAY_HALF();
  56         WRITE_SCL(HIGH);
  57         DELAY_HALF();
  58      }
  59
  60    /* get ack */
  61    WRITE_SCL(LOW);
  62    WRITE_SDA(HIGH);
  63    DELAY_HALF();
  64    WRITE_SCL(HIGH);
  65    do
  66      {
  67         DELAY_HALF();
  68      }
  69    while (READ_SCL() != HIGH);
  70    Ack = (READ_SDA() == LOW);
  71    DELAY_HALF();
  72
  73    INFO_(VIDEOPRT, "I2CWrite: %s\n", Ack ? "Ack" : "Nak");
  74    return Ack;
  75 }
  76
  77
  78 static UCHAR
  79 I2CRead(PVOID HwDeviceExtension, PI2C_CALLBACKS i2c, BOOL Ack)
  80 {
  81    INT Bit = 0x80;
  82    UCHAR Data = 0;
  83
  84    /* pull down SCL and release SDA */
  85    WRITE_SCL(LOW);
  86    WRITE_SDA(HIGH);
  87
  88    /* read byte */
  89    for (Bit = (1 << 7); Bit != 0; Bit >>= 1)
  90      {
  91         WRITE_SCL(LOW);
  92         DELAY_HALF();
  93         WRITE_SCL(HIGH);
  94         DELAY_HALF();
  95         if (READ_SDA() == HIGH)
  96           Data |= Bit;
  97      }
  98
  99    /* send ack/nak */
 100    WRITE_SCL(LOW);
 101    WRITE_SDA(Ack ? LOW : HIGH);
 102    DELAY_HALF();
 103    WRITE_SCL(HIGH);
 104    do
 105      {
 106         DELAY_HALF();
 107      }
 108    while (READ_SCL() != HIGH);
 109
 110    return Data;
 111 }
 112
 113
 114 static VOID
 115 I2CStop(PVOID HwDeviceExtension, PI2C_CALLBACKS i2c)
 116 {
 117    WRITE_SCL(LOW);
 118    WRITE_SDA(LOW);
 119    DELAY_HALF();
 120    WRITE_SCL(HIGH);
 121    DELAY_HALF();
 122    WRITE_SDA(HIGH);
 123 }
 124
 125
 126 static BOOL
 127 I2CStart(PVOID HwDeviceExtension, PI2C_CALLBACKS i2c, UCHAR Address)
 128 {
 129    /* make sure the bus is free */
 130    if (READ_SDA() == LOW || READ_SCL() == LOW)
 131      {
 132         WARN_(VIDEOPRT, "I2CStart: Bus is not free!\n");
 133         return FALSE;
 134      }
 135
 136    /* send address */
 137    WRITE_SDA(LOW);
 138    DELAY_HALF();
 139    if (!I2CWrite(HwDeviceExtension, i2c, Address))
 140      {
 141         /* ??release the bus?? */
 142         I2CStop(HwDeviceExtension, i2c);
 143         WARN_(VIDEOPRT, "I2CStart: Device not found (Address = 0x%x)\n", Address);
 144         return FALSE;
 145      }
 146
 147    INFO_(VIDEOPRT, "I2CStart: SUCCESS!\n");
 148    return TRUE;
 149 }
 150
 151
 152 static BOOL
 153 I2CRepStart(PVOID HwDeviceExtension, PI2C_CALLBACKS i2c, UCHAR Address)
 154 {
 155    /* setup lines for repeated start condition */
 156    WRITE_SCL(LOW);
 157    DELAY_HALF();
 158    WRITE_SDA(HIGH);
 159    DELAY_HALF();
 160    WRITE_SCL(HIGH);
 161    DELAY_HALF();
 162
 163    return I2CStart(HwDeviceExtension, i2c, Address);
 164 }
 165
 166 /* PUBLIC FUNCTIONS ***********************************************************/
 167
 168 /*
 169  * @implemented
 170  */
 171
 172 BOOLEAN NTAPI
 173 VideoPortDDCMonitorHelper(
 174    PVOID HwDeviceExtension,
 175    PVOID I2CFunctions,
 176    PUCHAR pEdidBuffer,
 177    ULONG EdidBufferSize
 178    )
 179 {
 180    PDDC_CONTROL ddc = (PDDC_CONTROL)I2CFunctions;
 181    PI2C_CALLBACKS i2c = &ddc->I2CCallbacks;
 182    INT Count, i;
 183    PUCHAR pBuffer = (PUCHAR)pEdidBuffer;
 184    BOOL Ack;
 185
 186    TRACE_(VIDEOPRT, "VideoPortDDCMonitorHelper()\n");
 187
 188    ASSERT_IRQL_LESS_OR_EQUAL(PASSIVE_LEVEL);
 189    if (ddc->Size != sizeof (ddc))
 190      {
 191         WARN_(VIDEOPRT, "ddc->Size != %d (%d)\n", sizeof (ddc), ddc->Size);
 192         return FALSE;
 193      }
 194
 195    /* select eeprom */
 196    if (!I2CStart(HwDeviceExtension, i2c, DDC_EEPROM_ADDRESS | WRITE))
 197      return FALSE;
 198    /* set address */
 199    if (!I2CWrite(HwDeviceExtension, i2c, 0x00))
 200      return FALSE;
 201    /* change into read mode */
 202    if (!I2CRepStart(HwDeviceExtension, i2c, DDC_EEPROM_ADDRESS | READ))
 203      return FALSE;
 204    /* read eeprom */
 205    RtlZeroMemory(pEdidBuffer, EdidBufferSize);
 206    Count = min(128, EdidBufferSize);
 207    for (i = 0; i < Count; i++)
 208      {
 209         Ack = ((i + 1) < Count);
 210         pBuffer[i] = I2CRead(HwDeviceExtension, i2c, Ack);
 211      }
 212    I2CStop(HwDeviceExtension, i2c);
 213
 214    /* check EDID header */
 215    if (pBuffer[0] != 0x00 || pBuffer[1] != 0xff ||
 216        pBuffer[2] != 0xff || pBuffer[3] != 0xff ||
 217        pBuffer[4] != 0xff || pBuffer[5] != 0xff ||
 218        pBuffer[6] != 0xff || pBuffer[7] != 0x00)
 219      {
 220         WARN_(VIDEOPRT, "VideoPortDDCMonitorHelper(): Invalid EDID header!\n");
 221         return FALSE;
 222      }
 223
 224    INFO_(VIDEOPRT, "VideoPortDDCMonitorHelper(): EDID version %d rev. %d\n", pBuffer[18], pBuffer[19]);
 225    INFO_(VIDEOPRT, "VideoPortDDCMonitorHelper() - SUCCESS!\n");
 226    return TRUE;
 227 }